1. Field of the Invention
The invention relates to a hearing device comprising at least two microphones, a processor and an output for further processing in a reproducer, the microphones being electrically coupled to the processor which comprises a first summer for providing a difference signal of the microphone signals, to which first summer an integrator is connected, and the output for further processing in a reproducer being connected to the processor.
2. Description of the Prior Art
Such a hearing apparatus is known from the international patent application WO 95/12961. This application relates to a directional microphone system in which three microphones are used. Of two microphones, the output signals are amplified both proportionally and integratingly and supplied to a summer.
In hearing apparatus, the directivity is very important to achieve a high audibility of speech. The acoustic signals should be selectively amplified: only the speech signals or other important audio information should be amplified, not the inevitable undesired noise.
There is therefore a need for highly directional hearing apparatus in which the directional characteristic of the hearing apparatus gives a good response to the difference in sound pressure between two discrete microphones.
The invention provides such a hearing apparatus, which is characterized in that the processor comprises a second summer providing a sum signal of the microphone signals, and to which second summer a proportional amplifier is connected, and that the proportional amplifier and the integrator are coupled on the output side to a third summer providing a sum signal of the proportional amplifier and the integrator, and that the third summer forms the output for further processing in a reproducer.
Thus, a flat frequency response and a nearly constant directional index can be achieved.
The invention can advantageously be used such that the hearing device comprises three microphones and two processors, of which microphones in each case two are connected pairwise to a processor, that a first processor is connected to a low-pass filter, that a second processor is connected to a high-pass filter, that the low-pass filter and the high-pass filter are connected to a fourth summer for providing a sum signal of the low-pass filter and the high-pass filter, and that the fourth summer forms the output for further processing in a reproducer.